High Flow Differential Cleaning
manufacturing
High Flow Differential Cleaning (MFS-TOPS-99)
Clean Complex Additively Manufactured Parts in Minutes - Not Hours or Days
Overview
Powder-based AM methods typically require post-fabrication component cleaning to remove residue powder from the surface and crevices of the part, a task that becomes increasingly difficult and time consuming with part complexity. Methods currently available to clean AM parts have significant drawbacks. Immersive cleaning using solvents or solutions can cause powder clumping. Forms of blasting (e.g., wet, bead, hydro, bristle, vacuum, etc.) work on line-of-site surfaces but are ineffective for recessed cavities. Such cleaning is typically manual, highly time consuming, and requires careful use of personal protective equipment to avoid powder inhalation. Thus, the AM market would benefit from a more automated, rapid, and effective method for cleaning complex parts.
The Technology
NASA developed this High Flow Differential Cleaning technology in response to in-house needs for a more automated and effective method to remove stubborn particles from complex parts fabricated using powder-bed-fusion equipment. The invention uses a large volume of pressurized air to quickly enter a cleaning chamber. Based on the Bernoulli principle and Continuity equation, the high flow results in significant air velocity and a decrease in pressure when airflow passes through smaller component orifices, which in turn removes remnant powder from the part. In one embodiment, the invention consists of a (1) high-pressure air compressor with ISO 8573 Class 2 drying capability, (2) a large pressure chamber with a fast-actuated valve system to, (3) a cleaning chamber containing various sensors, injection systems, (4) a test fixture designed for easy orientation adjustments, and (5) an expansion chamber allowing air to expand and drop in velocity, particles to settle, and filtered air to re-enter the room. This NASA technology can be implemented as a standalone cleaning system for powder bed fusion additively manufactured parts, or could be integrated into a packaged post-processing system offering. CT scans of complex NASA parts cleaned using a proof-of-concept system based upon the invention revealed very promising results.
NASA welcomes industry to test the cleaning speed and efficacy of the technology under an evaluation license.
Benefits
- Fast, automated process: Parts are cleaned in seconds (minutes when including load/unload time), instead of hours or days
- Effective cleaning: CT-scans of cleaned parts revealed effective particle removal
- Works on complex parts: Removes remnant powder lodged in small channels and passageways found in complex AM parts
Applications
- Powder-based additive manufacturing, including direct metal laser sintering (DMLS), electron beam melting (EBM), selective heat sintering (SHS), selective laser melting (SLM), and selective laser sintering (SLS)
- Post-processing of complex additively manufactured parts
Technology Details
manufacturing
MFS-TOPS-99
MFS-33553-1
MFS-33553-1-PCT
Similar Results
Self-Cleaning Germicidal Door Handle
As previously mentioned, doorknobs, levers, and handles are commonly manufactured using plastic or stainless-steel materials. Since bacteria and viruses can survive for extended periods of time on such materials, these objects can facilitate the transmission of pathogens between users. Furthermore, it is burdensome and costly for organizations to implement cleaning protocols where door handles are cleaned continuously. To address this issue, UV sterilization systems have been used for door handles. However, such systems often require bulky mounting equipment, possess sub-optimal aesthetics, and are high price point products leaving significant room for improvement.
To overcome the limitations of using cleaning agents, sprays, or bulky high-cost sterilizing systems, NASA developed an Ultraviolet Germicidal Door Handle. This invention largely resembles a conventional doorhandle; however, it contains a compact, far UV-C LED light device that attaches to the handle via mounting threads and disinfects surfaces (i.e., kills or inactivates pathogens). The device is controlled by a sensor that activates the UV-C light for a specified time to disinfect the surface after each use. After disinfection is completed, a timer sequence switches the light off and prepares for the next use. Due to the simple, thread-based mounting system, the UV-C LED is easily removable from the door handle. The UV-C LED has several convenient features including a USB charging port, I/O switch, and low battery indicator light.
The Ultraviolet Germicidal Door Handle greatly minimizes the risk of harmful pathogens, such as SARS-CoV-2, being transmitted between people using the same door. Various versions of the Ultraviolet Germicidal Door Handle could be marketed to accommodate different designs of door handles and levers.
Particle Contamination Mitigation Methods
The following methods can be used individually or in combination to generate superhydrophobic surfaces:
Synthesis of novel copolyimide oxetanes with unique surface properties
The technology is the synthesis of a polyimide coating or film with a modified surface chemistry shown in Figure 1. A minor amount of an oxetane reactant containing fluorine is added to the polyimide, and the oxetane preferentially migrates to the surface, enabling relatively high concentrations of fluorine at the surface, without compromising the functional performance of the bulk of the polymide coating/film.
The copolymers exhibit mitigation of particle adhesion and fouling from exposure to various particulate and biological contaminants and exhibit reduced surface energy and increased surface fluorine content at extremely low oxetane loadings relative to the imide matrix (see Figure 2). Additionally, the short fluorinated carbon chains do not bioaccumulate, reducing the environmental impact of these materials.
Modifying surface energy via laser ablative surface patterning
This method uses a laser to create nanoscale patterns in the surface of a material to increase the hydrophobicity of the surface (see Figure 2). The benefits of hydrophobic surfaces include decreases in friction and increases in self-cleaning properties. This is an advantageous method of surface modification because it is fast and single-step, promises to be scalable, requires no chemicals, could be applied to a variety of materials, and does not require a planar surface for patterning.
Activated Metal Treatment System (AMTS) for Paints
PCBs have been shown to cause cancer in animals and to have other adverse effects on immune, reproductive, nervous, and endocrine systems. Although the production of PCBs in the United States has been banned since the late 1970s, many surfaces are still coated with PCB-laden paints. The presence of PCBs in paints adds complexity and expense for disposal. Some treatment methods (e.g., use of solvents, physical removal via scraping) are capable of removing PCBs from surfaces, but these technologies create a new waste stream that must be treated. Other methods, like incineration, can destroy the PCBs but destroy the painted structure as well, preventing reuse.
To address limitations with traditional abatement methods for PCBs in paints, researchers at NASAs Kennedy Space Center (KSC) and the University of Central Florida have developed the Activated Metal Treatment System (AMTS) for Paints. This innovative technology consists of a solvent solution (e.g., ethanol, d-limonene) that contains an activated zero-valent metal.
AMTS is first applied to the painted surface either using spray-on techniques or wipe-on techniques. The solution then extracts the PCBs from the paint. The extracted PCBs react with the microscale activated metal and are degraded into benign by-products. This technology can be applied without removing the paint or dismantling the painted structure. In addition, the surface can be reused following treatment.
Alternative Transparent Coating Lotus Suitable for Optics with Vacuum Deposition Layer
In addition to previous LOTUS coating formulations, an additional optical formulation may be applied via vacuum deposition. This coating forms a top layer and may be applied in different thicknesses that serve to enhance its hydrophobic properties. The vacuum deposited material may comprise fluorinated ethylene propylene or a similar material. This coating is transparent and can be used on optical components or any other applications requiring a clear coating.
Completely biodegradable filtration system for waste metal recovery from aqueous solution
There is a significant need for an inexpensive biological approach to recover specific, targeted metals and other target materials in e-waste or other aqueous solutions that requires minimal input of resources, including energy. This invention is a method of removing or adsorbing a target substance or material, for example, a metal, non-metal toxin, dye, or small molecule drug, from solution, by functionalizing a substrate with a peptide configured to selectively bind to the target substance or material and to bind to the substrate. The substrate is fungal mycelium, and the naturally-occurring or bioengineered peptide is called a target-binding domain, which is chemically bonded to a selected solid substrate. The target chemical species binds to the target-binding domain and is removed from solution. The target can be any chemical species dissolved or suspended in the solution. Capture of the target by the substrate can isolate and allow removal of the target substance from solution, or for utilization in water filtration, or recovery of targeted chemical species from solution, particularly aqueous solution applications. The peptides used include (i) fusion peptides and/or proteins containing metal-binding domain sequence and optionally containing substrate-binding domain sequence; (ii) fusion peptides/proteins containing a metal-binding domain and a chitin-binding domain; and (iii) nucleic acids encoding fusion peptides and/or proteins containing metal-binding domain sequence. The technology enables simple scale up to a level that could be successfully implemented in an environment with limited resources, such as on a space mission or on earth in developing countries with poor access to clean water.